Risk Factors of Synchronous Breast and Thyroid Cancer: a Controlled Multicenter Study and Review of the Literature

Abstract

Background: Breast cancer (BC) is one of the most common cancers diagnosed in women in the United States. Thyroid cancer (TC) is also one of the fastest increasing cancer types in the United States, with most cases being papillary thyroid carcinomas. Objective: To identify possible risk factors for the synchronous or metachronous co-occurrence of breast and thyroid cancers. Methods: We carried out a study, which consisted of data from four gynecological clinics: two in Greece (Athens, Alexandroupolis, Ioannina) and one in Germany, collected from June 2017 to June 2020. The patients were divided into two groups: the first group consisted of 58 patients with breast cancer and a personal history of thyroid cancer. The second group (control group) included 50 patients with the same characteristics as to age, parity, type of pregnancy, treatment for sterility, polycystic ovaries, regularity of the menstrual cycle, breast density, BMI, family history of cancer, blood group rhesus and histological results of breast cancer. The data we collected were analyzed using version 20 of the SPSS statistical package. The Chi-square test was used for statistical analysis and a p-value<0.005 was considered statistically significant. Results: The only factors that seem to be related with the association of breast and thyroid cancer were: history of abortion and multiparity. Conclusion: In our study there is a higher chance of developing breast cancer after diagnosing thyroid cancer and vice versa. More than genetic mutations, a possible hormonal pathway of these two malignancies is possible. The hormonal change in women who had many children or abortions could be a risk factor to develop both cancers. More studies are necessary to confirm our findings.

Development of Histologically Verified Thyroid Diseases in Women Operated for Breast Cancer: A Review of the Literature and a Case Series

“…These data point out that ER play a role in the development of TC and in the increased rates of association between TC and BC. Zervoudis et al [ 22 ] hypothesized a possible hormonal pathway of these two malignancies since the hormonal change in women who had many children or abortions could be a risk factor to develop both cancers. Genetic predisposition in the co-occurrence of BC and TC could play an important role [ 23 ].…”